Making a dished polishing buff



April 23, 1963 s. D. KENT 'a1-AL 3,086821 MAKING A DISHED POLISI-IING BUFF Original Filed March 14. 1960 1 VENo I! amuel t United States arent 3,086,821 MAKING A DlSiD PLiSimG BUFF Stephen B. Kent, 557 Liberty St., Newburgh, NSY., and Smile! P. Crane, 1 Warwick Road, Great Neck, N.Y.

@riginal appiication Mar. 14, 1969, Ser. No. 14,625, now

Patent No. 3,087,289, dated Nov. 7, 1961. Divided and this appiication 9ct. 9, 1961, Ser. No. 143,779

11 Ciaims. (Ci. 309-21) This invention relates to making power driven bufng pads of the wood pile type and particularly to the formation of the peripheral portion thereof.

Such pads, while exible, have usually been made in disc form and each 'backed with a liexible duck or canvas sheet having a relatively hard edge. In using the buff to come into Contact with the work surface and instantane- I eat care is taken, the rapidly rotating hard edge may come into contact with the work surface and instantaneously burn olf the paint instead of polishing it.

Attempts have been made to prevent ysuch contact, as by the use -of a peripheral draw string, to pull the edge of the but rearwardly around a plate or backing cushion applied to the head of a polishing machine `and thereby to provide wool material at the edge of the buff ready to be interposed between the hard edge of the 'back sheet and the work when the cuter edge part of the buff is in use. Various Aother more or less eicient but relatively expensive means have yalso been suggested for maintaining the edge portion of the buff in a dished or forwardly convex position While in operation and thereby to anrange and maintain enough wool in front of lthe hard edge of the canvas back sheet to prevent burning of or damage to the work surface.

Such means have proven either to be too expensive or else they are impractical Vand shorten the useful life of the buff too much to permit the commercial adoption thereof, or `are not fool proof in that for example, they require *assembly to the buff or to the head of the polishing machine and are frequently lost or forgotten.

T he present invention therefore contemplates the provision of a method `of making 1a bufling pad in the general form of a disc land having la self-sustaining but flexible dished peripheral Wool-bearing portion integral with the remainder of the pad and interposing wool at all times between the Work and lthe edges of the backing sheets regardless of the angle at which the pad is held against the Work, the central portion also being dished.

The invention further contemplates formation of a resilient dished outer peripheral portion extending rearwardly from the intermediate normally undistorted dat body portion of the pad, and an oppositely dished central portion, the dished portions being inseparable parts of the pad free :of any backing or support and permanently biased toward the norm-al dished shapes thereof.

The invention further contemplates the provision of a simple method of making the pad including the shaping of the adhesively coated dished portions under vacuum and at room temperatures for a limited period sufficient to impart ya temporary set to such portions, which set becomes permanent when the adhesive lhas completely dried and hardened.

The various objects `of the invention will be clear from the description which follows and from the drawings, in which FIG. l is a. perspective view of the pad showing the self-sustaining yieldable dished edge portion.

FiG. 2 is a plan view of the pad showing the wider front or Wool-bearing sheet and the smaller rear backing sheet partly broken away.

FIG. 3 is la vertical sectional view of FIG. 2.

FIG. 4 is a vertical :sectional view of the pad tand of the means by which the vacuum is applied to the pad during the initial :or pre-drying operation.

FIG. 5 is au elevational view of the assembled partly dried and still moist pad showing the trimming operation.

FIG. 6 is a top plan View of FIG. 5.

FIG. 7 is a vertical 4section-al view showing the trimmed pad being shaped at its edge portion while being subjected to vacuum, and the central portion dished oppositely.

FIG. 8 is a fragmentary vertical sectional view tof the finished dried and permanently set dished edge portion `of the pad, and the similarly set central portion.

YIn the embodiment fof the invention illustrated herein, the wool pile or tufts 10 are stitched to the initially oversized front iiexible fabric sheet 11, of cotton duck, canvas or the like, leaving the peripheral .part tof said sheet bare of tufts (FIGS. 2 and 3). The similar rear backing sheet 12, of initially lesser diameter than the sheet 1v1, is adhesively secured to the sheet 11 by means `of a suitable viscous adhesive 13 of the moisture carrying type which is flexible when dry and set and which is preferably, though not necessarily, resistant to dry cleaning solvents. No adhesive is applied to the excess margin 14 of the sheet 11. The :reinforcing central washer 15 is adhesively secured to both sheets y11 and 12, both of the sheets and the Washer having registering holes therein forming the central attaching hole 16 of the assembly and by means of which the pad is securable to the head of a polishing machine.

It is desirable, before trimming the sheets to size, to dry the adhesive between the sheets which have been made wet by the absorbed moisture in the adhesive. The preliminary drying is carried out under vacuum as best seen in FIG. 4 'and has advantages which materially aid in the permanent shaping of the edge portion of the pad. 'Ihe untrimmed pad is inserted into the plastic bag .18 of flexible air-tight material, through the normally open mouth -19 at Aone end 20 of the bag. The [other end 21 is partially closed and communicates with the exhaust pipe 22 through which lair is withdrawn Ifrom the bag by means `of a suitable vacuum pump not shown. When the mouth 19 of the bag is temporarily closed as by the Weight 23 and the air is withdrawn rom the bag, much of the moisture is also withdrawn from the adhesive 13 to make it more viscous. Some of the moisture from the adhesive penetrates and is forced into and retained in the fibers `of the sheetsand maintains the sheets moist enough to permit the relatively easy shaping thereof later. At the same time, the adhesive lapproaches its setting point and is forced by the atmospheric pressure `on the bag, into the interstices of the fabric sheets to coat interior areas of the fibers thereof.

For long-drying adhesives which are highly resistant to dry cleaning solvents, the preliminary drying period may be as high as 45 minutes at room temperature. However, lfor adhesives of the latex type drying quickly but not resistant to such solvents, the preliminary vacuum drying step just described may be omitted and pressure applied to the sheets.

Before the adhesive has set and while it is still moist enough to permit manual sliding of the sheets to some extent over each other, the succeeding operations of trimming, adhesive-thickening and edge shaping are performed. As shown in FIGS. 5 and 6 the marginal portion of the sheet 11 'as well as a small part of the sheet 12 margin, are simultaneously trimmed off as by means of the reciprocating blade 27, while the sheets are still flat. The diameter of the thus trimmed flat sheets is the same for both, but is greater than the final diameter of the finished dished sheets of the shaped pad.

The assembled and trimmed flat pad 28 is now ready for shaping. It is placed on the wooden form 29 with the rear sheet 12 in contact with the top of and overhanging the form. The top edge portion 30 of the form has the desired convex and generally spherical curvature. The form and flat pad are inserted into the bag v18, the mouth `of Vthe bag then closed and air exhausted therefrom. Atmosp'heric pressure on the bag is transmitted to the pad and forces the projecting peripheral portion thereof downwardly and inwardly against the surface of the form to shape the pad into the desired dished form. Since at this point, the adhesive, though ystill wet, has approached the setting point, vacuum need be maintained only Ifor a relatively short time, or about 15 minutes at room temperature for the solvent resistant adhesive, heat being objectionable because the damp wool pile would be unavoidably distorted Were it heated. The adhesive remains moist but thick enough. to adhere well to the fibers, to be retained in the interstioes .of the fabric and to hold the pad in its dished form .outside of the vacuum until drying is complete and the adhesive hardens.

It may be noted that while the sheets 1.1.and 12 `are of relatively heavy and thick fabric, no wrinkling occurs at the dished edge part of the pad with the above described method of forming. When the extreme .free edge 31 of Vthe rear sheet 1.2 has been -forced back into its iinal position in the pad, said edge is considerably reduced in diameter las are all parts of the spherical or dished edge portion to `a decreasing extent =in the direction toward .the flat part of the sheet. However, the interstices between the fibers of the sheets are decreased in extent by the crowding together of Vsuch fibers, to compensate for the decrease in overall `diameter of the vpad assembly. Wrinkling is thereby avoided especially as the fibers are still somewhat damp and absorb some of the still moist adhesive and are also coated therewith.

The front wool-carrying sheet .11, initially or when dat, being of the same diameter as the sheet 12, is bent around .a curve of greater radius than that of the .curve of the `sheet 12 while the central body portions of both sheets remain in fixed contact. Consequently, the moi-st dished portion of the front sheet at 32 slides on the moist adjacent dished portion of the rear sheet during the shaping operation. The extreme edge 33 in its nal position no longer coincides with the edge 31, there being an exposed relatively narrow margin 34 on the sheet 12 adjacent said edge '31. Such margin is covered with adhesive. Some f the Wool tufts vprojecting from the sheet 11 are forced against the adhesive rand cover and adhere to the marginal portion 34 and prevent any possible contact thereof with the work. During the end part of the yfor-ming operation, the cross sectional shape of the fibers of the fabric may be changed from generally circular to generally oval because of the differences in the radii of curvature between the fron-t and rear surface of each sheet, the latter being less than the former. It is throught that more crowding occurs of the fibers of each -sheet at the rear surface of the dished portion than at its yfront surface, and lthat where the fibers are .crowded enough to come into contact, the cross sectional width at that point is decreased.

It will be understood that the central part of the bulf need not be dished, but may remain at if desired, in Which case the top surface of the shaping form as 29 also remains flat. Por insuring proper shaping of said central part in order to provide a iiat rearwardly depressed center 35 and a generally conical surface 36 joining the part 35 to the intermediate body portion 37, a resilient pad 3S of -foam rubber or the like is inserted into the central recess 39 of the form 29. The pad 38 transmits atmospheric pressure put on the bag 18 to the sheets 11 and 12 and presses them into the recess 39.

Since the greater part of the moisture has been removed from the adhesive during the shaping operation which is relatively fast, the adhesive, though still moist, has about set and is stiff enough after the shaping step to maintain the assembly in the shaped form thereof with no need for assistance in this respect, the moisture not evaporating fast enough under the vacuum to be completely extracted prior to the setting of the adhesive. The formed assembly is remo-ved from the vacuum bag and thoroughly dried until the adhesive becomes hard enough to resist deformation of the shaped edge while retaining its flexibility. Drying may be done at room temperature or under heat depending on the type of adhesive employed, but where heat is used, no pressure is exerted on the pile, as such pile may become distorted permanently under hea-t and pressure.

Should it be desired to have the free edges of the sheets even with each other, the margin 34 of the sheet 12 is trimmed 0E to coincide with the edge 33, or both edges are trimmed simultaneously to make the nal finished edges of the sheets coplanar. If desired, the extreme edge portions of the sheets may be stitched together to insure against possible separation thereof at the edges Where the stress is greatest should the adheive bond be broken. It will be undertood that the rear lface of the front sheet =11 is not flat because of the rearwardly projecting wool tuft bends. For that reason, the adhesive is preferably applied to the adjacent face of both sheets 11 and 12, though in some cases, a relatively thick coat of adhesive on the front face of the rear sheet is suiiicient.

It will be understood that the edge dished portion of the buff and the central dished portion are self-maintained in position and are more rigid than the intermediate body portion. Should either dished portion yield, as when put under pressure, it resumes its normal dished shape when the pressure thereon is released, being biased permanently toward such normal dished shape. It will also be seen that the side'curved area around the bend 32 is throughout provided with an adequate quantity of wool sucient to prevent contact of any part of the sheets with the work until the buff is worn out and that in eiective method is disclosed herein for making the i uif.

This application is a division of copending application Ser. No. 14,625 for Dished Polishing Disc, now Patent No. 3,007,289.

While certain specific forms lof the invention have herein been shown and described, various obvious changes may be made therein without departing from the spirit of the invention defined in the appended claims.

We claim:

1. The method of making a self-sustaining dished peripheral edge portion on a polishing buff comprising (a) placing a fabric sheet coated on the front face thereof with a moisture-containing adhesive on to the rear face of a Ifabric sheet carrying wool on the front face thereof,

(b) extracting part of the moisture from the adhesive by vacuum,

(c) and bending the edge portions of the adhering sheets into dished form until the adhesive has substantially set hard enough to maintain said edge portions dished.

2. The method of claim l, the moisture-extracting step allso forcing adhesive into and between the fibers of the s eets.

3. The method of claim 1, the bending operation being conducted by placing the sheets and a form supporting the sheets in a plastic exible bag and evacuating the air from the bag at room temperature to force the sheets against the form.

4. The -method of claim 1, the edge portions of the sheets slipping Vover each other during the bending operation and the marginal part of the rear sheet moving into a position overhanging the edge of the front sheet and having sucient adhesive thereon to engage and secure to said marginal part some of the wool projecting from the front sheet.

5. The method of making a permanently shaped selfsustaining dished edge portion on ia wool pile buff cornpr1s1ng (a) stitching a Wool pile to the front face of a fabric sheet.

(b) adhesively securing said sheet to another fabric sheet by means of moisture-carrying adhesive therebetween,

(c) extracting enough of the moisture from the adhesive to shorten the setting time thereof,

(d) and shaping the edge portions of both sheets into rearwardly dished shape on and in contact with a form inside of a exible bag subjected to vacuum and to atmospheric pressure on the outside of the bag until the setting point of the adhesive is closely approached.

6. The `method of claim 5, removing the buff `from the bag and completing the drying of the adhesive.

7. The method of making a polishing bui comprising (a) adhesively attaching together a Wool-carrying fabric sheet and a second yfabric sheet in face -to face relation throughout with moisture-carrying adhesive therebetween,

(b) placing the sheets inside of a flexible bag,

(c) and extracting moisture from the adhesive and simult-aneously applying atmospheric pressure to the sheets by subjecting the inside of the bag to vacuum to force part of the adhesive into the interstices of the sheets.

8. The method of claim 7, bending the edge portions of the sheets laterally rearwardly to dish the sheets in one direction while the bag is subjected to vacuum and simultaneously shaping the central portion of the sheets by `depressing said portion laterally rearwardly to dish said portion in 4the opposite direction.

9. The method of making va polishing buff comprising (a) stitching wool to the front face of the cent-ral part of an oversize fabric sheet leaving a marginal portion of the sheet free of Wool,

(b) coating the central part of the rear face `of the sheet and the front face of a similar smaller sheet with moisture-carrying adhesive,

(c) arranging the sheets coaxially with the adhesive therebetween,

(d) subjecting the assembled sheets and Wool to vacuum thereby to extract part of the moisture from the adhesive, to force the adhesive into the interstices of the sheets and to draw the sheets together,

(e) trimming the sheets while generally flat simultaneously to the same diameter,

(f) 'forming the periphery of the assembled sheets into a dished shape by vacuum =and atmospheric pressure while extracting a substantial part of the remaining moisture from the adhesive to impart a set to said periphery,

(g) and completing the drying of the adhesive after the assembled parts have been released from the vacuum.

10. The method of claim 9, and again trimming the edges of the sheets to make said edges coplanar.

11. The method of claim 9, and heating the dished assembly to complete the drying of the adhesive.

References Cited in the le of this patent UNITED STATES PATENTS 2,429,122 Crowley Oct. 14, 1947 2,783,176 Boicey Feb. 26, 1957 FOREIGN PATENTS 1,078,014 France May 5, 1954 

1. THE METHOD OF MAKING A SELF-SUSTAINING DISHED PERIPHERAL EDGE PORTION ON A POLISHING BUFF COMPRISING (A) PLACING A FABRIC SHEET COATED ON THE FRONT FACE THEREOF WITH A MOISTURE-CONTAINING ADHESIVE ON TO THE REAR FACE OF A FABRIC SHEET CARRYING WOOL ON THE FRONT FACE THEREOF, (B) EXTRACTING PART OF THE MOISTURE FROM THE ADHESIVE BY VACUUM, (C) AND BEING THE EDGE PORTIONS OF THE ADHERING SHEETS INTO DISHED FROM UNTIL THE ADHESIVE HAS SUBSTANTIALLY SET HARD ENOUGHT TO MAINTAIN SAID EDGE PORTIONS DISHED. 